EP2264219 to JSR Corp. discloses an organosilane chemical vapor deposition compound having the formula:
wherein R1 and R2 individually represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a vinyl group, or a phenyl group, R3 and R4 individually represent an alkyl group having 1 to 4 carbon atoms, an acetyl group, or a phenyl group, m is an integer from 0 to 2, and n is an integer from 1 to 3.
JSR Corp. disclose over 170 specific compounds that meet the formula, and those compounds probably do not exhaust the available iterations of the formula. JSR Corp. discloses at paragraphs 0033, 0045, and 0052, that the compound of the disclosed formula have 0 to 1 H atoms included in R1 and R2 from the viewpoint of ease of synthesis, purification, and handling or alternatively have 1 to 2 H atoms from the viewpoint of decreasing the boiling point of the compound and increasing the mechanical strength.
JSR Corp. further discloses the combination of the over 170 specific compounds with a porogen and an additional silane compound having the formula R6aSi(OR7)4-a, R8b(R9O)3-bSi—Oe—Si(OR10)3-cR11c, and —[R13f(R14O)2-fSi—(R15)g]—, with R6, R8 to R11, R13 and R14 individually representing a H atom, a F atom, or a monovalent organic group, R7 individually representing a monovalent organic group, R15 representing an O atom, a phenylene group, or a group shown by —(CH2)n—, a being an integer from 0 to 4, b and c individually being integers from 0 to 3, e being 0 or 1, f being an integer from 0 to 2, g being 0 or 1, h being an integer from 2 to 3, and n being an integer from 1 to 6 (para 0062). The pore forming agent may be any compounds having a ring structure (para 0094). The numerically challenging combinations are alleged to produce an insulating film that exhibits “more excellent” mechanical strength and a low relative dielectric constant (para 0067).
Depositions using combinations of precursors may provide films having dielectric constants and Young's Modulus that are an approximate average of the dielectric constant and Young's Modulus of the films produced by the precursors alone. This phenomenon is partially demonstrated in Comparative Example 1 of the present application, which summarizes Examples 2 and 14-18 of EP2264219. This phenomenon is further demonstrated in Comparative Examples 2, 4, and 5.
Additionally, any improvements in Young's Modulus results for a specific precursor or combination of precursors frequently occur with an increase in dielectric constant. This phenomenon is demonstrated in Comparative Example 1 of the present application, which summarizes Examples 14 to 17 of EP2264219. This phenomenon is further demonstrated in Comparative Example 6.
The need remains for insulating films having low dielectric constant and high mechanical strength.